
"""simple docstring"""



from math import factorial


def 			_UpperCamelCase						(    _A = 2_0   )     ->	int:





    """simple docstring"""

    _UpperCAmelCase        = 2 * n  # middle entry of odd rows starting at row 3 is the solution for n = 1,
    # 2, 3,...
    _UpperCAmelCase        = n // 2

    return int(factorial(_A   ) / (factorial(_A   ) * factorial(n - k   ))   )


if __name__ == "__main__":
 import sys

 if len(sys.argv) == 1:
  print(solution(2_0))
 else:
  try:
   a       :						Optional[Any]       		=		int(sys.argv[1])
   print(solution(n))
  except ValueError:
   print('''Invalid entry - please enter a number.''')

"""simple docstring"""



import warnings
from functools import wraps
from typing import Callable


def 			_UpperCamelCase						(    _A   )     ->	Callable:





    """simple docstring"""

    @wraps(_A   )
    def _inner_fn(*_A       ,   **_A   ):
        warnings.warn(
            (F"""'{fn.__name__}' is experimental and might be subject to breaking changes in the future.""")       ,   _A       ,   )
        return fn(*_A       ,   **_A   )

    return _inner_fn